The Invitation is one of the creepier slow-burn thrillers you're liable to see this year, and probably any other. It's full of the sort of Hitchcockian buildup of tension that few contemporary thrillers have the patience for, taking a creepy scenario—an invitation from the protagonist's ex-wife to a dinner party at the house they lived in together before the death of their child—and wringing every ounce of drama out of the discomfort that would come up in that situation. The entire film is about letting the viewer know that something is wrong, but delaying the reveal of exactly what that is for as long as possible—and getting into a position to tell that story in that way is something it took director Karyn Kusama a long time to do.

"My husband, Phil Hay, is one of the writers of the script. He and his cowriter, Matt Manfredi, wrote the script and originally just showed it to me for my comments, because they were thinking they might want to direct it," she recalls. "I put my hand up and said, 'If you guys decide not to, I absolutely have to direct it.' I angled myself toward the material as soon as I read it—there was something about its structural demand of the audience that I thought was just so uncanny and unusual and imaginative. I knew as soon as I read it that I had to direct it. It took a while to put it all together—to get the money, to find the cast—but in the end, I'm really happy that I can be talking about it now."

Kusama knows from long processes of bringing movies together. In her 16-year career, she's made four features—2000's Girlfight, the 2005 MTV adaptation Aeon Flux with Charlize Theron, the 2009 Megan Fox horror/comedy Jennifer's Body, and now The Invitation. And The Invitation—which she first read before she began working with Diablo Cody on Jennifer's Body—might be the longest-simmering of the lot. But what she learned about patiently putting a film together from that process can be downright instructive.

Film financing can be a tough game, and that's especially true when it comes to challenging, slow-burning psychological thrillers. Fortunately, it's one that's been disrupted by Gamechanger Films, the film fund that launched in 2013 to provide financing for movies directed by women. The Invitation is one of the early films from the fund—and while Kusama connected with them through more conventional means than answering an ad in the paper, her experience in working with a financier who trusted her to put her vision on the screen was unique.

"It was such a great experience to work with them—they're very hands-off, ultimately," Kusama says. "[Gamechanger president] Mynette Louie really seemed to understand the script, and when we screened the movie for the consortium of investors that work with Gamechanger, they all had smart, interesting notes to share—yet there wasn't the sort of pressure that comes when you read a bunch of notes to just do what you're told and execute the notes. It was a really positive experience."

A thriller like The Invitation works differently from a movie where we benefit from having a sort of narrative shorthand associated with the cast. To create the sort of immersive world that Kusama was after, she needed a cast without much baggage. There are familiar faces in The Invitation—Michiel Huisman's got a big presence from Game of Thrones, Orphan Black, and others, and John Carroll Lynch's turns on shows like The Walking Dead and The Americans has kept him in viewers' minds—but the film needed a cast that we believed in but with whom we didn't have strong associations, which was a challenge to assemble.

"We required a lack of cinematic baggage. You want to look at the actors and watch the characters they're playing, and not really be able to assign certainty to their aims or to their psyches—we needed to remain surprised by everyone," Kusama says. "Even if we've seen them in other work, we wanted to approach them with the philosophy that we couldn't assign a sense of previous knowledge or vibe. I hope this movie gave them the opportunity to play fairly well-realized characters, but not be people that we already know who they're going to be in the structure of the movie."

Kusama's career has included four features that all fit into different genres—sports drama, sci-fi adventure, horror/comedy, and now psychological thriller. (She's also directed episodes of Billions, The Man in the High Caste, Halt and Catch Fire, and more.) None of that necessarily prepared her for putting together a film that simmers the way that The Invitation does. So how do you build that level of tension?

"It's a bit mysterious, I think. Some of it happens while you're shooting, and before you're shooting, in the conception of your visual strategies. Some of it happens in the cutting room, when you have to train your heart and your eye to be seeing the movie for the first time, time after time after time, to understand how this particular choice or technique is working," Kusama says of her process. "All of those questions have to come into play."

There are concrete things she does as a filmmaker in The Invitation that draw on other movies ("What makes a lot of suspenseful films work is very, very particular points of view, and very subjective use of the camera," she says), but a lot of it here involves getting into the head of the protagonist.

"Our main character Will (Logan Marshall-Green) is fundamentally kind of a broken character, arriving at the scene of a haunted place for him, so I wanted to take advantage of that instability on his part and put the audience inside of his headspace, while also giving enough information to allow the audience to question whether or not he's a reliable translator of the evening," she says. "It was a combination of film techniques that make you feel unease, because you're not seeing everything. A lot of the best suspense operates on a careful withholding of information, as opposed to the doling out of information. I tried to be aware of all of that while I was making the film. But it's funny, because until I was really in the process of shooting and cutting, I wasn't thinking about the film in terms of genre mechanics. I wasn't thinking about suspense as much as I was, like, an emotional suspense. And that helped me, in that we're so aware of his unstable point of view and his fractured psyche that we're asking as many questions about his emotional health throughout the night as we are about what's going on on a larger scale."

The less you know about The Invitation going into it, the better. Of course, that presents a challenge, too, because you have to give people enough information about the film that they actually, you know, watch it. Kusama recognizes that challenge—and so she was excited to partner with Drafthouse Films for the release of the movie, since they understood the need to balance the two objectives.

"I have a child, and I have limited time, so I can't just be going to the movies at any time of day or night—films need tools to get people in the theater, and yet our tools specifically needed to remain fairly mysterious," she says. "They needed to have a sense of profound questions—where is this headed? Where could this head? We really tried to stay on top of it and create a teaser and a trailer that, while they intimated that things were going to probably get very grim, it's not entirely clear how or why. I don't know if we've really succeeded in that, but it was definitely our aim. Going in cold makes it a really fun and crazy theatrical experience, but I recognize that people often need to know, if they want a psychological thriller, they will eventually get it."

Like with Gamechanger and the financiers, the distributor understanding what her goals were and how best to frame the film made a big difference for Kusama. "Drafthouse Films sold themselves to us simply by saying that they really believed that people need to go into this film as cold as possible," she says. "They gave themselves a very high bar to have to reach in terms of creating marketing materials that would be compelling, mysterious, and gripping, but also be very conscious of how much information they were allowing to spill out of the edges of those materials."

At this point in Kusama's career, she's not in the business of chasing trends. Instead, what the protracted process of getting The Invitation made (and then released—the film premiered at SXSW in March of 2015, more than a year ago) taught her is that the most important thing in her career is getting to make the movies that she wants.

"I don't know if I would be able to keep doing this if I didn't feel like I had some creative freedom because, in the end, as much as this is a business and as much as films and television are commodities of a sort, ultimately the blood, sweat, and tears are pretty sizable if you're the director," she says. "I'm at a point where I'm willing to take myself seriously enough to ask for what I need—and now I'm just asking for more freedom, even if that means fewer resources. I want the ability to really investigate the work that I'm doing, as opposed to playing defense on every count. Making The Invitation was such a great alchemy—a script that came from within the family, then being able to make it at a low and challenging number, but with people who supported my creative execution from top to bottom, and then to have it be distributed by people who understood the film, respected the film, and respected me enough to hear and engage my opinions and the opinions of our creative team on how we were getting this movie to people. It's taken a lot of years to figure out how to get the movie out there in a manner that we feel good about, but I feel like we actually did that with this movie. It's great, because it feels like we've already won."

The Invitation opens in select theaters and VOD on April 8th

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